


The Madwoman's Book

by lusteralliance (orphan_account)



Series: Demon!Byleth [3]
Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Ashen Demon, Blood, Demon!Byleth - Freeform, Father-Son Relationship, Gen, I CANT BELIEVE JERALT FINALLY HAS A FULL NAME, heyyy changed the warnings bc of the biting scene, this has gotta be my favorite volume of this series so far
Language: English
Status: Completed
Published: 2019-08-25
Updated: 2019-08-25
Packaged: 2020-09-26 08:27:18
Rating: General Audiences
Warnings: Graphic Depictions Of Violence
Chapters: 2
Words: 1,145
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20386693
Author URL: https://archiveofourown.org/users/orphan_account/pseuds/lusteralliance
Summary: Byleth gets a hold of his namesake. Even though the little demon can't read, Jeralt has a nagging feeling that he understands what lies within it.





	1. I

**Author's Note:**

> yall.....

"Baba?"

Jeralt looked up from his woodworking, Byleth's small voice coming from the bedroom having distracted him. He was kind of carving a bear, but since he'd only ever seen a real bear once, it did _not_ look like one.

"Yeah, Byleth?"

He heard Byleth's little bare footsteps coming down the hallway as he placed his deformed hunk of wood and whittle (which was probably disappointed in him too) on his desk. Byleth was walking around on his own now, since he was old enough to grow impatient waiting for Jeralt to drop everything and move him a couple feet to the left. Plus, he was five now. If he were a normal kid, he'd be at school, running and getting muddy.

Unfortunately, he was not a normal kid. Although his mood swings were starting to get more controlled, his antlers were growing in, and Jeralt hated that he didn't notice Byleth's weird tailbone actually being the beginnings of...a tail.

He toddled in just now, staring at what was in his little hands. Jeralt leapt to his feet when Byleth held up the madwoman's book, his blue eyes pleased. His stubby tail wagged, poking out from under the hem of his oversized, dark gray shirt.

"Green!" he announced.

"Byleth, put that down," Jeralt murmured, walking slowly over. Byleth put the dark green book on the ground obediently, staring at the golden letters that spelled his name with curiosity. Then, he squatted down and flipped it open. "Byleth!"

The little boy saw the dragon and the demon and gasped for just an instant before Jeralt swept him quickly up into his arms and headed away. 

"You shouldn't mess with that thing, I don't—AAGH!"

Tines of agony shot through him, and the mercenary stumbled as Byleth sank his fangs into his unguarded shoulder. Jeralt grabbed the demon and yanked at him, but his bite was sure, and Jeralt nearly ripped a chunk of his own flesh right off.

"Ngh—Byleth! Byleth, let go! What's gotten into you?" he howled, and he fell to his knees, blood splattering from his wound to the ground. He'd have to clean it all over again. Byleth growled into his bloodied shirt, and Jeralt grunted as he pinched the child's ear and started to pull. Suddenly, Byleth let go and whined with pain, falling to the wooden floor and writhing, his face covered with Jeralt's blood.

His eyes were black and furious; there was some kind of otherworldly light to them. They glistened with something alien as he growled and fought to free himself from Jeralt's grasp. His antler buds were glowing, almost like tongues of flame.

That book….

Then, in a heartbeat, Byleth blinked, and his narrowed eyes, now blue, widened with fear and pain. Jeralt let out a trembling breath as he let go of the ashen demon's ear. He pressed that hand to his shoulder, wincing.

"Ba...Baba…?" Byleth whimpered, lying on his back, and he licked his lips, swallowing some of Jeralt's blood. He scrambled upright and wiped his face with his hands, and when he saw the blood dripping from his fingers, and the mess of torn flesh that was Jeralt's shoulder, he screamed and vomited in shock.

"Byleth! Oh, gods, Byleth, it's okay, it's okay," Jeralt gasped, grabbing Byleth and holding him close to his chest. Byleth coughed and retched and sobbed, kicking at Jeralt's arm in distress. "Gods...Byleth…."

"Baba…!" Byleth wailed, and Jeralt squeezed his eyes shut, trying to ignore the throbbing pain in his shoulder and trying desperately to calm the child in his arms. That book was evil. He did not need to read it to know.


	2. II

Byleth sniffled as he hugged his doll to his chest, his eyes wide as he stared blankly into space from where he sat in bed. Jeralt stroked his hair gently, his shoulder wound cleaned and dressed. The floor would have to have some more work done to return it to its previous state, but Jeralt would tend to it when Byleth was asleep.

The madwoman's book was closed and locked in a wooden chest on a high shelf. It had been in Jeralt's dresser drawer before. He could not read the ancient tongue it was written in, and he knew for a fact Byleth couldn't either. He was homeschooled, if "homeschooled" meant shapes, colors, "yes," "no," "please," "thank you," and avoiding strangers. He did _not_ teach him the ancient tongue.

But Jeralt did have to consider: Byleth was a vessel of ancient power. Surely that power traced back to the times this tongue was spoken. He could not read the signs over village shops, but what if he could read the madwoman's book?

That was one matter, but the contents were another. What was it that Byleth read (if he did read it) that made him go ballistic? Perhaps there was a spell of some kind, one that made him lose the scraps of humanity Jeralt had pieced together in him for just a little while. Or maybe it was the picture. The illustration of the first ashen demon, its one eye black with a white pupil, mouth open in a fanged snarl, forked tongue flicking, antlers glistening with some kind of fiery essence. It might've awakened some beast inside Byleth; the vessel.

Jeralt shivered and rubbed Byleth's antler buds, and Byleth leaned his head against Jeralt's arm. He hadn't shed a single blood tear today, even after everything. He was a brave boy. 

Jeralt had a feeling that Byleth no longer liked the demon part of him, his true self. That was partly his doing. It made him guilty, but he knew it was for the best. 

Then, he considered something else; if the ashen demon was a danger to humanity, but not an asset, why didn't the madwoman just kill Byleth when Jeralt had hidden in her fortune telling shop?

The thought disgusted Jeralt, even more so that for a split second, he considered it. How could he even think of such a thing? Byleth was a child. He was chosen as the vessel of the ashen demon's power. It was not his fault. 

"Are you sleepy, Byleth?"

"Mm...no…."

"Okay. Do you want me to stay here?"

"Yes, Baba…."

"Okay, I'll stay."

Byleth was shivering. His blue eyes were haunted, as if he had seen spirits; maybe he did. The spirit of the first ashen demon. Jeralt lowered his head and kissed the child between his budding antlers, and he smiled when Byleth squeezed his doll, his eyes closing just a little. The mercenary had never kissed him before, and Byleth seemed to take comfort in it. He vowed to do it more often, for his sake.

Something was amiss with that madwoman's book, and until Jeralt figured out what it was, he would protect Byleth no matter the cost.

**Notes for the Chapter:**

> thank read


End file.
